Friction welding apparatus

ABSTRACT

A friction welding apparatus and a method for its use is disclosed where the apparatus includes a plurality of interchangeable components including a drive system, an actuator assembly, a support system and a control system, the combination operable to friction weld a workpiece to a valve body.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to an improved friction weldingapparatus and related apparatus for its use and application in thefield. More specifically, the present invention is directed to aportable friction welding apparatus operable via low pressure airsources commonly found in industrial settings, and methods for its use.

2. Description of the Prior Art

In many settings, and especially industrial settings, it is oftendesirable to attach two members or workpieces via a high strength, finegrain weld. Such a weld is usually performed via a conventional arc oropen flame welding procedure. However, in applications where volatile orcombustible gases are present, it is not usually possible to use an arcor open flame welding procedure due to the attendant danger of fire orexplosion.

One of the solutions proposed to address the above problem includes theuse of a friction weld procedure. The friction welding process relies onheat generation between rubbing surfaces to provide a material fluxwhich may be forged to produce an integral bond between the twosurfaces. There are generally two recognized methods of supplying energyto form a friction weld: direct drive friction welding, sometimesreferred to as "conventional" friction welding, and inertial welding.

In conventional frictional welding, one of the workpieces is attached toa motor-driven unit and rotated at a predetermined, constant speed,while the other member is maintained in a fixed, stationary orientation.When the appropriate rotational speed is reached, the two workpieces arebrought together and an axial force is applied. Heat is generated as aresult of the friction generated by interface of the respectivesurfaces, which interface continues for a predetermined time or until apreset amount of upset takes place. Thereafter, the rotational drivingforce is discontinued and the rotation of the workpiece is stopped. Theaxial force between the two members is maintained or increased, however,for a predetermined period of time to finalize the weld. The weldproduct result from a conventional friction weld process ischaracterized by a narrow heat affected zone, the presence ofplastically deformed material around the weld, and the absence of afusion zone.

A number of disadvantages exist with the direct drive or conventionalfriction welding process. One such disadvantage is the overall bulk ofsuch a system, since a typical direct drive friction weld apparatus isusually both large and cumbersome. Moreover, conventional frictionwelding apparatus also typically include complex electronic controls forcontrolling the different forces which must be applied and forcontrolling the drive means in a selective manner to monitor relativerotation of the workpieces. In rigorous applications such as thosepresented in the industrial environment, such electronic controls areoften prone to failure. Moreover, the presence of electronic controlsrequires the presence of an electronic power source which is often timesunavailable in the industrial setting.

Yet another problem which occurs with conventional friction weldingarises when the two workpieces are initially brought together. At thisstage, there is significant initial friction between the workpieces and,therefore, a considerable increase in the energy required to overcomethe initial friction. This problem is further complicated in weldingrotational workpieces to stationary workpieces due to wide variations infrictional torque throughout the weld cycle. On initial contact of thewelding surfaces, there is a relatively high frictional torque which isshortly followed by a requirement for inertial energy which persistsuntil a flux of hot metal is established. However, this energyrequirement is temporary in nature and ceases after the resistive torquehas been overcome. When the flux is established, the resistive torquefalls to a level during the "burn-off" and "upset" phases which maytypically be as low as some twenty-five percent of the initial peaktorque. During this phase, axial pressure is maintained and the contactsurface of both members are carbonized, in the instance of a carbonsteel, thereby adding to the flux. This upset phase continues until thedriving torque is removed after which time the flux cools, the weldfuses and the resistive torque increases.

The above-noted problems have been addressed in the prior art by thedevelopment of drive motors capable of supplying sufficient torque toovercome initial friction forces. Such a drive motor is generallyacceptable in relatively stationary friction welding apparatus. However,this proposed use of high power drive motors, due to their large powerrequirements and weight, are unacceptable to the design of a portablefriction weld apparatus.

Inertia friction welding was developed to address the abovedisadvantages of prior art "conventional" friction welding techniques.Contrasted with conventional friction welding, in inertial frictionwelding the speed of the rotating workpiece continuously decreasesduring the friction stages of the procedure. In inertial frictionwelding, the rotating workpiece is coupled to a flywheel which isaccelerated to a predetermined rotational speed. During the weldprocess, the drive motor is disengaged and the workpieces are forcedtogether in an axial direction. This axial force causes the forgingsurfaces to rub together under pressure. The kinetic energy stored inthe rotating flywheel is ultimately dissipated as heat as a result offriction between the workpieces. As a result of such friction, the speedof the flywheel decreases until stoppage during which time the axialforce may be increased or maintained. The total time for the wheel tocome to rest depends on the average rate at which the energy is beingremoved and converted to heat.

Three variables are presented by the inertial welding technique. Theseinclude the movement of the inertia of the flywheel, the initialflywheel speed, and the axial pressure between the workpieces. The firsttwo variables dictate the total amount of kinetic energy available toform the weld. The required axial pressure is dictated by the materialsto be welded and the interface area. The energy contained within aflywheel is determined by its mass and rotational speed.

One such inertial friction welding apparatus is disclosed in U.S. Pat.Nos. 4,702,405 and 4,735,353 as issued to Allan R. Thomson, et al. Thefriction welds apparatus described by Thomson is somewhat portable andutilizes a dual drive means where the second drive means includes aflywheel. In operation, the Thomson apparatus utilizes the first drivesmeans to establish a preliminary number of revolutions per minute in therotating workpiece before it is engaged to the stationary workpiece towhich a weld is desired. Upon engagement, the spinning member begins todecelerate at a rate commensurate with the axial load and the initialrevolutions per minute. Sufficient rotations of the spinning member,however, are maintained by the energy stored in the flywheel, whichenergy is hopefully sufficient to maintain rotational movement toovercome the initial frictional forces whereafter the first drives meansmaintains rotation of the spinning member until the weld is completed.

Disadvantages, however, also exist for the inertial friction weldapparatus described by Thomson. One such disadvantage is the requirementfor an extremely high pressure air source and high pressure fluid flowto power the apparatus. Accordingly, the Thomson apparatus is notadapted to use pressurized air sources conventionally found atindustrial facilities, but instead must utilize high pressure airsupplied by special compressor units which must necessarily accompanythe apparatus to the job site. This need for an additional source ofpressurized air decreases to a considerable degree the portability ofthe Thomson system and also enhances the costs and flexibility of itsoperation. Moreover, the high pressure requirement also enhances thecomplexity of the architecture of the air motor and thus enhances theoverall maintenance requirements of the system.

Other disadvantages include the requirement in the Thomson device for aflywheel to store inertial energy, which flywheel rendering the Thomsonapparatus both heavy and bulky.

SUMMARY OF THE INVENTION

The present invention addresses the above and other disadvantages ofprior art friction welding apparatus by providing a lightweight,portable apparatus which is able to form a fine grain, forged frictionweld by use of pressurized air sources commonly available at industrialfacilities.

The friction weld apparatus of the present invention generally comprisesa drive means, an actuator component, a clamp assembly and a controlmeans and a method for its use. Unlike conventional and prior weldingapparatus, the present invention is not contained within a singlehousing but instead is componentized with operational integrationachieved by unique coupling elements. Such componentization isadvantageous because it allows for ease in inspection and replacement ofdamaged components while other components remain in operation.

In a preferred embodiment, the present invention is fully automatic andthus independent of the operator during the welding process. This offersthe benefit of removing the operator from the immediate area of thefriction weld itself which, if the procedure includes a leaking valve,may present the potential of a high temperature or noxious environment.

The present invention offers yet other advantages over the prior art inthe manner of safety systems. In a preferred embodiment, the controlsystem offers manual emergency shutoff controls and timed shut down forwelds exceeding a preset time in the event of a failure of equipment orin the weld itself. Further, the control system of the present inventionmay be isolated from the air supply connector, thus enhancing the safetyand portability of the welding apparatus in welding operations.

Moreover, the present invention is lightweight and operable off of airsupply sources conventionally found in industrial facilities, thusenhancing the flexibility of its application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of one embodiment of the frictionwelder of the present invention and each of its various components asdrawn along an axis "A".

FIG. 2 includes multiple views of the upper clamp section of the presentinvention including a proximal end 2A, a side view 2B and a distal end2C.

FIG. 3 is a cross-sectional view of one embodiment of a coupling sleeve.

FIG. 4 includes multiple views of one embodiment of a shaft couplingelement, including an end view 4A and a cross-sectional view 4B.

FIG. 5 includes multiple views of one embodiment of an actuator topcover including a cross-sectional view 5A and an end view 5B.

FIG. 6 includes multiple views of one embodiment of the actuator adaptercoupler of the present invention including a distal end view 6A, across-sectional side view 6B and a proximal end view 6C.

FIG. 7 is a side view of one preferred embodiment of a fitting adaptedfor use with the present invention.

FIG. 8 includes multiple views including end side cross section views 8Aand 8B of the logic block component.

FIG. 9 is an isolated side view of the actuator shaft.

FIG. 10 includes multiple views of an anti-rotation means including adistal side view 10a and an end view 10b.

FIG. 11 includes multiple views of the lower support member, including afront view 11A, a top view 11B and a side view 11C.

FIG. 12 is a schematic view of the control system of the presentinvention.

FIG. 13 is a detail view of the air motor and drive shaft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The friction weld apparatus 2 of the present invention is set forth atFIGS. 1-12 and generally comprises a drive means 3, an actuatorcomponent 5, a clamp component 8 and a control means 200. Thesecomponents are integrally coupled in a manner described below.

By reference to FIG. 1, drive means 3 preferably includes an air motor 4which may include a conventional air motor or a modification thereofdepending on the horsepower and torque output requirements for thefriction weld apparatus as will be discussed herein. Alternatively,other drive and power means, e.g., electrical, mechanical, or hydraulicpower sources are also envisioned within the spirit of the presentinvention. It is desirable, however, that any such alternative powersource generate sufficient torque and horsepower and be of a lightenough weight as to carry out the objectives of the present invention ina portable friction weld apparatus.

In a preferred embodiment, air motor 4 should generate no less than 0.5horsepower and 1 footpound of torque, and in a preferred embodiment willgenerate between 2-3 horsepower and generate some 2-3 footpounds oftorque. In order to enhance the overall portability of the system, airmotor 4 should weigh no greater than some seven pounds, and preferablysome three pounds. In a preferred embodiment, air motor 4 may include anIngersoll Rand Model No. 88H90 air motor or a comparable power source.Air motor 4 is operable via the pressured air sources ordinarily foundat industrial facilities which generally provide air pressure in therange of 90-125 pounds per square inch.

As illustrated in FIGS. 1 and 13, air motor 4 includes an air inlet 150at a first or distal end when viewed with respect to a workpiece 500,and a drive shaft 151 oppositely disposed with respect to inlet 150along a longitudinal axis designated "A". In one contemplatedembodiment, drive shaft 15 1 includes a spindle 72 which in oneembodiment may include a terminal threaded end 152.

Air motor 4 is itself disposed within a protective housing 32 which maybe formed of one or more components or access panels to allow for readyaccess and inspection. Housing 32 may be formed of molded aluminum,plastic or other strong, lightweight materials. Housing 32 defines atits distal end a connector 30 receivable to a supply of pressurized air(not shown) via coupling line 300. Coupling line 300 also carriescontrols to drive means 3 and other components of the apparatus 2 aswill be further described herein. In a preferred embodiment, line 300 isprovided with a quick disconnect coupling 29 at its proximal end toenable ready attachment and detachment of line 300 from connector 30.Such a quick disconnect feature is desirable in transportation and setup of the apparatus as well as when an emergency disconnect of the powersource might be necessary.

Generally stated, actuator component 5 is adapted to translaterotational movement created by drive means 3 as well as produce thenecessary forging pressure required to yield an acceptable friction weldbetween a workpiece 500 and a stationary member 550, e.g., a valve body.As illustrated in FIG. 1, actuator component 5 comprises a housing 60defining a longitudinal bore 61 therethrough, a sleeve 38 slidablydisposed in said bore and responsive to an axial movement means 62,where said sleeve 38 itself defines a bore therethrough in which anactuator shaft 79 is rotatably disposed about a radial bearing 36 and athrust bearing 39, where bearings 36 and 39 are embedded in sleeve 38.

The translation of rotational movement induced by drive means 3 thoughshaft 151 is accomplished by an actuator adapter coupler 34 asillustrated in FIGS. 1, 6 and 13. The rotation of air motor spindle 72is communicated to actuator shaft 79 and ultimately to workpiece 500 aswill be further described herein. Adapter coupler 34 is slidablyreceivable in the distal bore 102 of a shaft coupling element 35. (SeeFIG. 4). Referring to FIG. 6, coupler 34 comprises a cylindrical sleeve141 defining differing diametrical bores 140 and 142. In a preferredembodiment, bore 140 is disposed in the proximal end of coupler 34 anddefines an hexagonal end cross-section slidably receivable to actuatorshaft 79 and adapter nut 91 as will be further described herein. In apreferred embodiment, distal bore 142 is threaded to receive theterminal, proximal end 152 of spindle 72.

Air motor spindle 72 is fixedly coupled to actuator 5 via a shaftcoupling element 35 as illustrated in FIG. 1 and more specifically atFIGS. 4A-B. Coupling element 35, along with other elements of thecoupling assembly as described below, allows for quickconnect/disconnect of drive means 3 from actuator 5, and morespecifically the drive spindle 72 from actuator sleeve 38. Couplingelement 35 preferably includes a cylindrical sleeve 101 defining a multidiameter bore 112 therethrough, said bore 112 receivable at its distalend 102 to coupler 34 as earlier described and at its proximal end 104to the distal end 38A of actuator sleeve 38. As illustrated, the boredefined at distal end 102 is smaller in diameter than the bore definedat proximal end 104. Bores 102 and 104 are preferably spaced by asmaller diameter bore 109 receivable to the terminal end of shaft 79.Actuator coupling sleeve 38 is fixedly maintained on the proximal end ofcoupling element 35 via fasteners (not shown) threaded through radiallypositioned apertures 103. In such a fashion, rotation induced by airmotor 4 is translated to shafts 151 and 79, while coupling element 35and sleeve 38 are maintained in a fixed, nonrotating orientationrelative to drive means 3 and actuator 5.

By reference to FIGS. 1, 3 and 5, drive means housing 32 is rigidly heldin a spaced relationship vis-a-vis actuator 5 by a coupling sleeve 33and to a lesser degree by actuator top cover 50. By reference to FIG. 3,coupling sleeve 33 comprises a cylindrical body 120 defining alongitudinal bore 122 therethrough, where the distal end 123 of bore 122is adapted to slidably receive the proximal end of drive means housing32 as illustrated in FIG. 1. The longitudinal position of housing 32within sleeve 33 is maintained by a radial spacer 124. The proximal end125 of bore 122 is adapted to slidably receive shaft coupling element 35as described above and as illustrated in FIG. 1. The proximal end 125 ofsleeve 33 is also provided with two oppositely disposed, elbow shapedlocking grooves 121 receivable to keys threadedly disposed in apertures170 formed in coupling element 35. In a preferred embodiment, it isdesirable that sleeve 33 define a inner diameter closely approximatingthe outer diameter of the distal end of shaft coupler element 35 so asto ensure a close fit therebetween.

The assembly defined by the combination and interconnection of couplerelement 35 and sleeve 33 is slidably receivable within actuator topcover 50. Referring to FIG. 5, top cover 50 comprises a generallycylindrical sleeve 110 defining a longitudinal bore 112 therethroughwhere said bore 112 has an inner diameter matching the outer diameter ofcoupler element 35 and sleeve 33, when mated. The connection assemblydescribed above as comprised of coupler element 35, coupler sleeve 33,top cover 50 and adapter coupler 34 allow for the ready coupling and/orremoval of drive means 3 and actuator 5 to effect inspection or repair.

Actuator housing 60 is comprised of actuator top cover 50 and a logicblock component 6, the combination defining a coaxial ring or cavitytherebetween. Cover 50 and logic component 6 in combination with anaccess plate 51 form a pressurizeable chamber 47 in the aforereferencedcavity to accommodate axial movement means 62. Axial movement means 62comprises an actuator cylinder or piston 41 slidably disposed withinchamber 47 and fixedly coupled to sleeve 38, a series of inlet ports 42and 45, and a fluid sensing element 48. In the embodiment illustrated inFIG. 1, cylinder 41 is supported by a series of radially spaced, axiallydisposed tie rods 40 which are coupled at each end to cover 50 and logicblock 6. See FIG. 10. Piston 41 is provided with conventional sealingelements, e.g., O-rings about its outer radial diameter to maintain aseal upon its reciprocation within chamber 47. All sliding surfaces arepreferably lubricated with a Teflon® based, low friction, long lastinggrease to reduce wear therebetween.

In a preferred embodiment, cylinder or piston 41 is maintained in afixed rotational orientation with respect to chamber 47 during both theburn off phase and the forging period of the friction weld. This isaccomplished by the nonrotational interaction between shaft 79 andsleeve 38 as previously described via embedded bearing 36. Maintenanceof a stationary, non-rotating orientation of cylinder 41 is alsoaccomplished by a antirotation rod 611 situated inside chamber 47. Byreference to FIG. 10, rod 611 is axially disposed between thelongitudinal ends of chamber 47 through piston 41. Rod 611 is providedwith one or more sealing elements, e.g., O-rings, to preserve the sealon the proximal and distal sides of cylinder 41 to allow each side tomaintain a differential pressure. In this fashion, rod 611 mechanicallyprevents the rotation of cylinder 41 in chamber 47.

As noted, axial movement means 62 enables the formation and maintenanceof a selected forging pressure between the workpiece 500 and astationary member 550, e.g., a valve body. This axial movement andpressure is accomplished as a result of the differential pressurecreated across the distal and proximal ends of actuator cylinder 41 whenchamber 47 is pressurized via inlet ports 42 and 45. When a selectedfluid, e.g., air, is introduced into chamber 47 under pressure via inlet42, pressure is created behind actuator cylinder 41 which is fixedlycoupled to sleeve 38. Cylinder 41 is then urged in a axial directiontoward stationary member 550. This axial movement initially results inthe contact necessary between the workpiece 500 and the stationarymember 550 to achieve burn-off and upset, and ultimately achieves theforging pressure necessary to complete the weld. In this connection, thecontact pressure and duration can both be closely modulated by theoperator or preset as will be further described herein.

When the weld has been completed, air pressure through inlet 42 isterminated. Fitting 7 is then disengaged from the apparatus 2. This maybe accomplished manually by decoupling drive means 4 and actuator 5 toexpose adapter nut 91. Shaft 79 is then manually turned via nut 91 in acounter-clockwise direction to back off chuck 187 from fitting 7.Alternatively, when pressure through inlet 42 is eliminated, air motor 4may be reversed to disengage fitting 7 from chuck 187 after which timeair pressure is then introduced ahead of cylinder 41 via inlet 45 toreturn piston 41 to its original, retracted position.

In a preferred embodiment, actuator lower end port 45 is provided with afluidic sensing element 48. Sensing element 48 functions to provide theoperator control of the weld to a predetermined upset conditionregardless of the material constituting the workpiece and the stationarymember, and regardless of the varying times needed to accomplish afusion weld. Sensing element 48 comprises a detachable cylindricalelement which is activated by the closure of actuator cylinder 41. Thisis accomplished by a disruption of air flowing through sensor 48, whichdisruption creates an increased signal to control means 200. Fluid flowfrom the activated sensing element 48 is channeled into logic blockcomponent 6 via a connecting passageway (not shown) formed in logicblock 6 and operatively coupled to an air pressure source via centralmeans 200 via fluid sensor transducer 363.

Actuator chamber 47 is pressurized by the introduction of air channeledthrough logic block component 6 vis-a-vis an air supply source 600 asearlier described. Logic component 6 contains fluidic and pneumaticcomponents and includes a number of mechanical fluid passages to providefor sensing, logic, control and purging functions. A cross-sectionalview of logic component 6 may be seen by reference to FIG. 8 in which isillustrated a purge hole 355, a check valve 357, e.g., a Clippard ModelMCV-1, a pressure release valve 359, e.g., a Clippard Model MAV-3P, aneedle valve 361, e.g., a Clippard Model MNV-3P, and a transducer 363,e.g., a Clippard Model 1022. A schematic illustrating fluid flow throughlogic block 6 is presented at FIG. 12.

Referring to FIG. 8, transducer 363 provides for interpretation andtransmission of the fluid signal generated by sensing element 48, and isdesigned to provide fluid flow to and from element 48 independent ofother fluid control elements located in logic block 6. Transducer 363provides the pressurized fluid flow required for the sensing and thepurging processes while creating a low pressure area at feedback line26. This area of low pressure is important to avoid the reception offalse sensing signals by control means 200. The architecture oftransducer 363 is such that low pressure can be achieved during the timefluidic sensing element 48 is inactive by the use of a venturi effectand/or the use of high subsonic or supersonic air flow through a nozzlethat creates a low pressure pick up point for line 26 until element 48is activated. When element 48 is activated, blocked fluid flowinterrupts the venturi effect and causes sensing pressure to feedbackline 26 to increase to the level required to activate logic system 17via transducer 14, quick coupling element 54 and other control feedbackelements as will be further described herein. Pressure relief valve 359may be located in logic block component 6 as illustrated in FIG. 8, ormay alternatively be located in actuator 5 or other isolated locations.Valve 359 is mechanical-pneumatic in that it is either manuallycontrolled or controlled through automatic control systems as previouslydescribed and as will be described in more detail below.

Logic block component 6 also includes a fluidic-pneumatic pressuremodulation control system 55 as coupled to line component via logicfeedback quick coupling element 54. Control system 55 modulates thefluid flow entering inlet port 45 by first providing a delay time periodand then increasing the forging pressure to actuator 5 for a selectedduration until a maximum or selected forging pressure is achieved.Control system 55 also provides a mechanism to maintain a selectedforging pressure until the friction weld process is completed.

As noted, coupling element 54 is operatively coupled to component 300,logic block 6 and to transducer 52. Logic block component 6 alsoincludes a clamp weld chamber purge pressurization port 49. Port 49serves to channel fluid flow from inactivated fluidic sensor 48 to clampcomponent 8 to provide a positive pressure which keeps out explosivegases during the friction weld process. Air flowing from sensor 48through port 49 passes through passage 355 and into weld chamber 65 andthen through purge ports 49, 58 and 355, to the atmosphere, the resultbeing to provide a positive pressure in chamber 65 to keep out explosivegases emitted by member 550.

Actuator shaft 79 is rotatably coupled at its distal end to couplingsleeve 35 as described above, and at its proximal end to a workpiece 500which, in one preferred embodiment, constitutes a fitting 7 of thegeneral configuration illustrated in FIG. 7. A detailed view of actuatorsleeve 38 including inner shaft 79 is illustrated at FIG. 9. Asillustrated, shaft 79 is provided with a threaded distal end 180 and aproximal end 181 defining a head 184. Threaded distal end 180 isreceivable to adapter nut 91 receivable in coupler 34. As illustrated,head 184 describes a larger diameter than shaft 79 and defines athreaded fitting chuck 187 as will be further described herein inrelation to fitting 7.

In the embodiment illustrated in FIG. 7, fitting 7 includes a distalattachment end 63, a heat sink shaft 61, a fitting weld plate 60 and abottom upset shaft 62. Attachment end 63 is preferably externallythreaded to allow for quick and accurate installation of fitting 7 tochuck 187 and shaft 79. The threaded fitting top also assuresconcentricity for an effective friction weld. Heat sink shaft 61 allowsfor the dissipation of excess heat so as to protect other parts offriction weld apparatus 2. Fitting weld plate 60 permits attachment ofthe upset parent material so as to provide for a significantly strongerconnection at the weld site than the strength of the parent material.

It is contemplated that fitting 7 may be constructed from stainlesssteel, e.g., a 316 stainless steel, although other metals, plastics andceramics are also contemplated as being within the spirit of the presentinvention. Fitting preferably describes a bore 99 partially disposedtherethrough about attachment end 63, where said bore 99 is internallythreaded so as to be operative compatible with the leak sealingtechnique taught and described in U.S. Pat. Nos. 5,052,427 and5,062,439.

Stationary member 550 is held in a rigid, fixed position relative tofriction weld apparatus 2 and more specifically workpiece 500 by clampassembly 8. Clamp assembly 8 comprises an upper 64 and lower 67 clampsection. Upper clamp section 64 is attachable to actuator 5 immediatelyadjacent logic block component 6. In one preferred embodiment, upperclamp section 64 is generally planar in configuration and defines distal131 and proximal 133 ends as illustrated in FIG. 2. Distal end 131 isgenerally rectangular in cross-section and defines an axially disposedbore 132 therethrough, where said bore is preferably frustro-conicallyshaped to accommodate proximal end or head 184 so as to define a weldcontainment chamber 65. Chamber 65 serves to isolate sparks and radiantheat generated during the friction weld process in combination with aspark containment molding compound and the introduction of a purge fluidas further described herein. The terminal end of chamber 65 defines aweld seal extension element 66 which serves to provide a guide forsituating workpiece 500 relative to stationary member 550. Asillustrated, distal end 131 is provided with a number of spacedapertures 138 to accommodate contentional threaded fasteners to secureclamp section 64 to actuator 5.

The proximal end 133 of upper clamp section 64 is generally elongate inshape with apertures 136, 137 being provided in each of the terminalends or wings 139 to accommodate fasteners (not shown) threaded throughthe lower clamp section 64 as will be further discussed below. Lowerclamp section 67 is adapted to hold a variety of workpieces 550 ofvarying sizes and configurations, and thus acts as a universal couplerclamp. These workpieces may constitute circular valves or workpieces ofenumerable other geometries. As illustrated in FIGS. 1 and 2, and morespecifically in FIGS. 11A-C, lower clamp section 67 comprises agenerally "U" shaped retaining arm 71 defining two terminal ends 134 and136. In the embodiment illustrated in FIGS. 11A-C, arm 71 defines aseries of linear sections connected at a 45° angle. Alternately, otherconfigurations for arm 71, e.g., those having a circular or arcuate topsection, are also envisioned within the spirit of the invention.Retaining arm 71 is preferably provided with a plurality of radicallyspaced apertures 70 threadedly receivable to spacing rods 141. Rods 14 1may be independently threaded in apertures 70 to contact and hold agiven stationary member, e.g., a valve body 550. In this connection, ifmember 550 is irregular in configuration, it can nevertheless be held ina selected, fixed position vis-a-vis apparatus 2 by individually movingrods 141 radially inwardly toward member 550 so as to establish acontacting relation therebetween. Once lower section 67 is placed aroundvalve body 550, it is then secured to upper clamp section 64 viafasteners (not shown) receivable in threaded apertures 143 formed in theterminal ends of retaining arm 130.

The operation of the various steps of the friction weld processconducted by the present invention and the actuation of the variouscomponents constituting such process is governed by control means 200.As illustrated in FIG. 1, line 300 is connectable to control means 200at its outlet end via fluidic pneumatic embedded feedback line couplingelement 18. Coupling element 18 serves to couple the embedded fluidicpneumatic logic input feedback line 26 and the embedded fluidicpneumatic air motor pressure input feedback line 25 without interferencefrom normal air flow from drive means 3. Further, coupling element 18isolates both signals and permits bringing the fluidic input signalsinto drive means housing 32, and, ultimately, through various pressurelines to the fluidic pneumatic logic system 17 via transducer 14 as willbe described below and as is illustrated in the schematic diagrampresented at FIG. 12.

Line 300 is comprised of a number of components including fluidicpneumatic control coupling line 24, embedded fluidic pneumatic air motorpressure input feedback line 25, embedded fluidic pneumatic logic inputfeedback line 26 and coupling element 27. Coupling line 24 houses both apressurized air conduit as well as control and sensing elements whichare operatively coupled to coupling element 18. Coupling line 24 iscoupled to both ends of coupling element 27, thereby providing forfluidic connection between logic component 6 and control means 200.Feedback line 25 is internally disposed within coupling line 24 in acoaxial relationship therebetween and provides a means for transmittingpressure information from drive means inlet 150 to a pressure gauge 23via coupling element 18. Feedback line 26 is also internally disposedwithin coupling line 24 and operates to transmit signals from transducer52 to transducer 14 via coupling element 18. Line 300 is provided at oneend with a coupling `T` element 28, which element 28 provides forisolation from the pressurized energy air flow from critical controlsignals while permitting control air flow to logic component 6.

Control means 200 is coupled at its inlet end to an air supply 600,preferably a plant air supply, via air supply line 400 and quickdisconnect coupling 10. In a preferred embodiment, coupling 10 includesa mechanical valve 12 which permits manual shut-off of the air supply.As earlier described, control means 200 is coupled to drive means 3 andactuator 5 by a coupling line 300 which preferably includes both an airsupply conduit as well as control feedback lines so as to provide forremote operation of the friction welding apparatus 2 by the operator.

Control means 200 is contained within a free-standing housing 13 whichin one embodiment may include a sleeve 13A and two end plates, 13B and13C. In the illustrated embodiment, end plates 13B and 13C provide forconnection for the various fittings which facilitate the pneumatics andfluidic energy and control functions as will be described below. Controlmeans 200 generally includes a fluidic-pneumatic multi-port controltransducer 14, pneumatic-mechanical logic system 17, for example anAroflex 6 unit, pilot pressure actuated pneumatic valve 19, for examplea Skinner valve, and volume couplers 20. Transducer 14 permits theacceptance of pneumatic signals from logic block 6 to reset and shutdown friction weld apparatus 2, including, but not limited to signalsfor an "And/Or Control Function"; emergency shut down by means of inputfrom the mechanical valve 16, shut down by means of input from time outvolume couplers 20 and/or an input from transducer 52.

Control means 200 also preferably includes a fluidic-pneumaticmechanical logic system 17. Logic system 17 performs a number of logicfunctions including, but not limited to, controlling the pilot pressureactuated pneumatic valve 19 as will be further described below. Logicsystem 17 also accepts various inputs from the transducer 14 as well asperforming timing functions for the "controlled time-out devices". Theterm "controlled time-out" as used herein is a preset time greater thanthe maximum time ordinarily required to complete a weld utilizing afriction weld process. The logic system 17 provides for control of theenergy to the isolated components of the system 2. Valve 19 provides airto air motor 4 as well as logic component 6. Valve 19 is adapted tospecifically conform to the flow and response requirement to create afriction weld between workpiece 500 and member 550. Emergency time outvalve couplers 20 are also located within housing 13 and function toprovide for timed shut off control of the energy to the isolatedcomponents of the system 2. In a preferred embodiment, couplers 20 areadapted to match the flow characteristics of logic system 17.

Control means 200 also includes a mechanical-pneumatic actuator meansand valve 15 and emergency deactivation means and valve 16. Valve 15 islocated in housing 13 and is operator controlled to begin the automaticfriction welding process. When engaged, valve 15 sends a pneumaticsignal to fluidic-pneumatic system 17. Valve 16 is also located inhousing 13 and is also operator controlled. When actuated, a pneumaticsignal is sent to the fluid-pneumatic logic system 17, thereby shuttingdown the welding operation. In a preferred embodiment, control means 200also includes a pressure gauge 23 which permits the operator to monitorfluid pressure at inlet 31 subsequent to the opening of valve 12. Gauge23 is operatively coupled to embedded fluidic pneumatic air motorpressure feedback line 25 which in turn is coupled to coupled element18.

The interaction of control means 200, logic block 6, and othercomponents in the relative interaction may be reviewed by reference toFIG. 12.

As will be described in more detail below, plant air is provided toapparatus 2 via plant air compressors which distribute air at around 90psi. This compressed air source is coupled to control panel 13 viacouplers 10, 11 and 12 as above-described. Filtered plant air is carriedthrough tubing 22 to start valve 15 and stop valve 16. Air from valve 15is transmitted to a flip-flop which constitutes a component of logicsystem 17. The flip-flop is also known as a by-stable control elementwhich when actuated creates a signal from a preset port. When an inputsignal is observed, the normal actuated signal is terminated and asignal is switched to another port. A pressure signal at a reset portwill switch the flip-flop back to its original "on" port.

In the event of a manual emergency shut-down, air from stop valve 16 istransmitted to "or"logic block transducer 14. Transducer 14 serves as amulti-port transducer to accept several air signals to reset theflip-flop as the system dictates.

A signal from the emergency "time out" system is received from volumechamber 20 in the event of a system shut-down failure. This "time out"system is comprised of logic system 17 and volume chamber 20.

The signal from "or" logic block transducer 14 is transmitted to theflip-flop located in system 17 either by sensor 48, emergency stop valve16 or the emergency "time out" system. The flip-flop located in logicsystem 17 is a pneumatic device energized by plant air at port 14.

An air pressure signal from start valve 15 to flip-flop set port 16located in system 17 initiates the system. Reset and system shut-down isobtained by an air pressure signal from valve 16 to the flip-flop portlocated in system 17. When the system is shut down, air is vented to theatmosphere through the flip-flop normally on the port located in system17.

An air pressure signal from the flip-flop initiates the emergency timerlocated in system 17 comprised of flow restrictor and volume chamber 20and opens the main high flow pilot actuated valve 19. The flowrestrictor is located in system 17 and is adjustable for setting varioustimes to shut down the system 2.

Air flow from the flip-flop located in system 17 exists through thenormally "off" port 18, and rechannels air to the pressure port of valve19. Valve 19 then receives high pressure air from internal air line 23.

Air line 300 carries air to air motor 4 and logic block 6. Air is fed to"or" logic transducer 14 through embedded air line 26. Air motor 4 ispowered until shut-off by sensor 48 through an input to the reset portof the flip-flop located in system 17 via transducer 52, quick couplingelement 54, embedded sensing line 26 and "or" logic transducer 14. Airmotor 4 uses plant air at a nominal value of 90 psi and approximately100 cubic feet per minute.

Fluidic transducer 52 separates sensor 48 pressure from feedback line 26signal and essentially constitutes a venturi effect with high pressurerecovery and low sensor feedback pressure. However, when sensor 48 isblocked, e.g., by cylinder 41, the venturi effect is disrupted andfeedback line 26 becomes pressurized and sends a high pressure signalback through embedded air line 26 to the "or" logic transducer 14 wherea signal is sent to reset the flip-flop in logic system 17 to shut downthe system by removing positive pressure from pilot actuated valve.

From the time air motor 4 is initiated the pressure to chamber 47 isgradually increased over time to provide first a zero and then anincreasing forging pressure until a maximum forging pressure is obtainedand locked in by valve 357. Check valve 357 as located in logic block 6is effective in maintaining forging pressures until a reasonablecool-down of the weld is achieved. Valve 359 is used to manually relievethe forging pressure at a selected and predetermined time.Alternatively, forging pressure may be automatically relieved via afluidic timer.

As illustrated in FIG. 12, it is desirable in a preferred embodiment toinclude means to run a system check or diagnostic on apparatus 2. Thismay be accomplished by a monitoring of system air pressure through aport disposed in actuator 5 or upper support 64.

The operation and use of the welding apparatus of the present inventionmay be described as follows. In the instance where a leaking valve hasbeen located, actuator 5 is coupled to the valve body 550 via clampcomponent 8. This is accomplished by placing lower element 67 around thevalve body 550 and then securing element 67 to upper element 64 viafasteners threaded in apertures 136 and 143 as previously described.Body 550 is now locked within component 8 yet is still moveable in threedimensions. Body 550 is immovably secured with respect to actuator 6 byselective movement of rods 141 through apertures 70 until valve body 550is fixed in a desired location via workpiece 500 and 64.

The friction weld apparatus 2 is then coupled to a plant air source viacoupling line 400. Plant air is supplied to the system after openingvalve 12 to permit regulated plant air to enter the system throughsupply line 400. Plant air is normally regulated to 80 to 100 pounds persquare inch and is prefiltered to remove debris and water.

In initiating the friction welding operation, the operator firstdetermines that desired plant air pressure and flow capability areinsured by reference to a regulator pressure gauge (not shown). Theoperator then depresses the mechanical-pneumatic start button and valve15 which introduces a pneumatic control signal to logic system 17.System 17, having received the "start" signal, then commands valve 19 toopen and to send air flow to various parts of the system includinginternal parts of logic system 17 through line 300. Logic elements 17initiate several operations including, but not limited to, activatingstop button and valve 16, activating an internal timer for the emergencytime-out volume coupler 20, activating the internal re-set port wherethe system can be shut down by couplers 20, valve 16 or sensing element48. All three of the system "shut-down" elements, couplers 20, stopbutton or valve 16 and sensing element 48, are operatively coupled via aseries of "or" type elements which process control information from anyor all of the input.

Coupling line 300 permits pressurized air from passing through valve 19to enter air motor 4 through inlet 150 and coupling 29. Pressure levelinformation at inlet 150 is fed back to pressure gauge 23 throughpressure lines embedded in line 300. Additionally, pressurized air issent to logic block component 6 via the fluidic pneumatic embeddedfeedback line coupling element 28 located in coupling "T" element 27.

Clamp 8 is purged with pressurized air via purge passageway 69 which islocated in upper clamp section 64 in weld containment chamber 65. Airintroduced through passage 69 in this fashion serves to keep explosivegas out of the area immediately proximate the contact point between 500and 550 so as to prevent possible detonation by heat or sparks.

Workpiece 500 is snugged against member 550 by introducing air throughair inlet 42. When workpiece 500 and valve body 550 are in contactingrelation, a spark retardant, e.g., an inflammable molding compound (notshown) is placed around workpiece 550 to prevent sparks generated duringthe friction weld process. Molding compound may be made from a hightemperature pliable material, e.g., a synthetic clay, and provides for apositive seal for the purge gas which then provides a positive pressurein weld containment chamber 65 for purposes of safety.

Upon the introduction of pressurized air, air motor 4 commencesrotational motion. Once air motor 4 is actuated at a optimum operationalspeed, pressurized air is directed to logic block component 6 via quickcoupling element 54, pressurization lines 56 and by means of discretefluidic logic passageways 57 to the actuator fluidic pneumatic pressuremodulation forging control system 55, fluidic sensing element 48, clampweld chamber purge port 49, purge passage 58 and positive purge passage69.

The control system located in logic block component 6 then actuatesforging control system 55 and transducer 52. Forging control system 55controls the axial movement of actuator cylinder 41 which, as noted,provides the axial force required to develop forging forces anddiscretely increases the forging pressure over a given time period byair flow into inlet 42. This control method permits initial torque inthe friction welding process to remain at a low level until the processhas been initiated and the "dry" friction welding forces drop to a zerovalue.

As the welding process proceeds, the terminal end 62 of component 7becomes upset and reduces in size, thereby permitting cylinder 41 andshaft 38 to move forward in an axial direction. At a predetermined pointat which component 7 will become welded to the substrate of valve body550, fluid sensing element signals transducer 52 via line 26, couplingelement 28, coupling element 54, transducer 14 and logic system 17, atwhich time control system 200 commands valve 19 to close and shut offall pressurized air flow to the system. In a preferred embodiment, valve19 provides for a selective time delay in shutting down to assureoptimum weld completion. At this point in the process, forging pressureis maintained at its maximum level on cylinder 41 to again assureoptimum forging of component 7 during the post-weld cool-down period. Itis contemplated that a weld may be completed utilizing theabove-described process in some thirty seconds with a cool-down periodof some sixty seconds.

During the shutdown period, pressurized air flow is discontinued therebyresulting in a return of the purge pressure through port 49 to ambientconditions. After a delay, e.g., sixty seconds, the forging pressureinduced behind cylinder 41 is released either via pressure relief valve53 (not shown), a controlled timer or other method. Once forgingpressure has been reduced, actuator shaft 38 may be manually retracted,or retracted by use of air motor 4 or alternately, by disconnecting airmotor 4 via coupling 29 and de-spinning shaft with coupler nut 37.

As evident from the above description, the friction weld apparatus ofthe present invention is operable without operator intervention duringthe weld cycle. In this connection, the entire control of the tool isautomatic to give single step actuation for the weld cycle.

Although particular detailed embodiments of the apparatus and methodhave been described herein, it should be understood that the inventionis not restricted to the details of the preferred embodiment. Manychanges in design, composition, configuration and dimensions arepossible without departing from the spirit and scope of the instantinvention.

What is claimed is:
 1. A portable welding apparatus for fusion welding agiven workpiece to a stationary member where the fusion weld processincludes a burn-off phase, an upset phase and a fusion period,comprising:a drive means adapted to produce a selected rotational speedin an axially disposed shaft; an actuator operatively engaged with saiddrive means comprising:a housing; means to translate the rotationalmotion of said shaft to the workpiece; movement means to urge theworkpiece in an axial direction relative to the stationary member at aselected pressure for the burn-off phase and the fusion period; whereinsaid drive means and said actuator are operatively coupled via a quickdisconnect assembly comprising a shaft coupling element, a couplersleeve and a housing element, where said shaft coupling element, when inan engaged position, is slidably disposed within the coupling sleevewhich in turn is slidably disposed within the housing element; a supportremovably engageable to said actuator housing and adapted to hold thestationary member in a fixed axial relationship relative to saidworkpiece; and control means to selectively regulate the duration of theburn-off and upset phases and the fusion period.
 2. The apparatus ofclaim 1 wherein said shaft coupling element is threadedly coupled tosaid drive means shaft and slidably coupled to said translation means.3. The apparatus of claim 1 wherein the translation means comprisesasleeve slidably disposed in said actuator housing and defining alongitudinal bore therethrough where said sleeve is operatively coupledto said movement means; and a shaft rotatably disposed within saidsleeve in a coaxial relation thereto.
 4. The apparatus of claim 1wherein the support is comprised of an upper and a lower element, wherethe upper element is fixedly secured to the actuator housing and thelower element includes a support arm releasably coupled to said upperelement, where said lower element includes at least one radially movableattachment element adaptable to position the stationary member in afixed, spaced relationship via said workpiece.
 5. The fusion weldingapparatus of claim 1 wherein said control means is remotely positionablerelative to said air motor and said actuator by a support and controlline.
 6. The apparatus of claim 1 wherein said housing further defines aweld chamber which accommodates the second end of said shaft and saidworkpiece in a spaced relation.
 7. The apparatus of claim 1 wherein themovement means includes a pressurizable chamber defined within saidactuator housing and disposed in fluid communication with a source offluid, wherein a cylinder is slidably and axially disposed within saidchamber and coupled in fixed relation to said workpiece such that theintroduction of said fluid in said chamber results in a selected axialmovement of said cylinder so as to urge said workpiece into contact withsaid member.
 8. The apparatus of claim 7 wherein said movement means isfixedly coupled to said sleeve.
 9. A portable welding apparatus forfusion welding a given workpiece to a stationary member where the fusionweld process includes a burn-off phase, an upset phase and a fusionperiod, comprising:a drive means adapted to produce a selectedrotational speed in an axially disposed shaft; an actuator operativelyengaged with said drive means comprising:a housing; means to translatethe rotational motion of said shaft to the workpiece; movement means tourge the workpiece in an axial direction relative to the stationarymember at a selected pressure for the burn-off phase and the fusionperiod;a support removably engageable to said actuator housing andadapted to hold the stationary member in a fixed axial relationshiprelative to said workpiece; control means to selectively regulate theduration of the burn-off and upset phases and the fusion period; andwherein said actuator also defines a weld chamber partially disposedabout the terminal end of said shaft and said workpiece where saidapparatus also includes means to maintain a positive pressure in saidchamber during the fusion weld process.
 10. The apparatus of claim 9where the weld chamber is further defined by a barrier of a malleablecompound placed between said actuator and said member about, but inspaced relation to, said workpiece.
 11. The apparatus of claim 9 whereinsaid drive means and said actuator are operatively coupled via a quickdisconnect assembly comprising a shaft coupling element, a couplersleeve and a housing element, where said shaft coupling element, when inan engaged position, is slidably disposed within the coupling sleevewhich in turn is slidably disposed within the housing element.
 12. Theapparatus of claim 9 wherein the support is comprised of an upper and alower element, where the upper element is fixedly secured to theactuator housing and the lower element includes a support arm releasablycoupled to said upper element, where said lower element includes aplurality of independently and radially movable attachment elementsadaptable to position the stationary member in a fixed, spacedrelationship via said workpiece.
 13. The fusion welding apparatus ofclaim 9 wherein said control means is remotely positionable relative tosaid drive means and said actuator by a support and control line.
 14. Anapparatus for friction welding a workpiece to a stationary member wherethe welding process includes a burn-off phase, an upset phase and afusion period, the apparatus comprising:an air motor disposed within ahousing, where said motor defines at one end an axially disposed shaftand at a second end a fluid inlet, where said shaft is rotatable at asufficient speed to create said burn-off and upset phases between saidworkpiece and the stationary member; an actuator operatively coupled tosaid air motor via a quick release coupling, where said actuatorincludes:a housing defining a cylindrical bore and a pressurizablechamber; a shaft rotatably disposed in said bore and operativelyengageable with the shaft of said air motor at one end and to theworkpiece at a second end so as to translate the rotation of said airmotor shaft to said workpiece; a piston slidably disposed within thechamber of said actuator housing and fixedly coupled to said shaft,where said piston is moveable in an axial direction upon the selectiveintroduction of pressure into said chamber; a support engageable to saidactuator housing and adapted to maintain the stationary member in afixed axial relationship relative to said workpiece; and control meansto selectively regulate the pressure exerted by and the duration ofcontact between said workpiece and the stationary member wherein saidcontrol means is remotely positionable relative to air motor and saidactuator by a support and control line.
 15. The fusion welding apparatusof claim 14 wherein said support includes a base plate and an attachmentelement wherein the combination is adapted to hold the member in a fixedposition relative to said workpiece.
 16. The apparatus of claim 14 wheresaid shaft is rotatably disposed in a sleeve which is fixedly coupled tosaid piston.
 17. The apparatus of claim 14 wherein said piston isprovided with means to prevent its rotation vis-a-vis said housing. 18.The friction welding apparatus of claim 14 further including a fluidsensing element operatively disposed within said chamber to monitorfluid pressure on said piston.
 19. The fusion welding apparatus of claim18 wherein said fluid sensing element is remotely monitorable by theoperator.
 20. An apparatus for fusion welding a workpiece to astationary member where the welding process includes a burn-off phase,an upset phase and a fusion period, the apparatus comprising:an airmotor disposed within a housing, where said motor defines at one end anaxially disposed shaft and at a second end a fluid inlet, where saidshaft is rotatable at a sufficient speed to create a burn-off phasebetween said workpiece and the stationary member; an actuatoroperatively coupled to said air motor via a quick release coupling,where said actuator includes:a housing defining a cylindrical bore and apressurizable chamber; a shaft rotatably disposed in said bore andoperatively engageable with the shaft of said air motor at one end andto the workpiece at a second end so as to translate the rotation of saidair motor shaft to said workpiece; a piston slidably disposed within thechamber of said actuator housing and fixedly coupled to said shaft,where said piston is moveable in an axial direction upon the selectiveintroduction of pressure into said chamber;a support engageable to saidactuator housing and adapted to maintain the stationary member in afixed axial relationship relative to said workpiece; control means toselectively regulate the pressure exerted by and the duration of contactbetween said workpiece relative to the stationary member; and whereinsaid housing further defines a weld chamber which accommodates thesecond end of said shaft and said workpiece in a spaced relation. 21.The friction welding apparatus of claim 20 where said apparatus isfurther provided with means to maintain a positive pressure in said weldchamber during the welding process.
 22. A portable welding apparatus forfusion welding a given workpiece to a stationary member where the fusionweld process includes a burn-off phase, an upset phase and a fusionperiod, comprising:a drive means adapted to produce a selectedrotational speed in an axially disposed shaft; an actuator operativelyengaged with said drive means comprising:a housing; means to translatethe rotational motion of said shaft to the workpiece; movement means tourge the workpiece in an axial direction relative to the stationarymember at a selected pressure for the burn-off phase and the fusionperiod; a support removably engageable to said actuator housing andadapted to hold the stationary member in a fixed axial relationshiprelative to said workpiece; and control means to selectively regulatethe duration of the burn-off and upset phases and the fusion periodincluding a means to gradually increase a forging pressure connected tosaid movement means.
 23. The apparatus of claim 22 wherein said drivemeans and said actuator are operatively coupled via a quick disconnectassembly comprising a shaft coupling element, a coupler sleeve and ahousing element, where said shaft coupling element, when in an engagedposition, is slidably disposed within the coupling sleeve which in turnis slidably disposed within the housing element.